Effects of prophylactic supplementation with oral calcium boluses on peripartum calcium, urine pH and health in a commercial Jersey herd supplemented with anionic salts

Abstract Text: The objectives of this study were to evaluate the effect of prophylactic supplementation with oral calcium boluses after calving on peripartum serum calcium and urine pH levels, as well as the prevalence of ketosis and endometritis.  Multiparous Jersey cows from a 3,500 herd were randomly assigned to control [no calcium supplementation (n = 67)] or treatment [2 oral calcium boluses (n = 64), (QuadriCalMINI, Bio-Vet, Barneveld, WI)].  The first calcium bolus was given at 2:30 h after calving (SD ± 1:54 h) and the second at 18:21 h after calving (SD ± 11:56 h).  Coccygeal blood and midstream urine were collected immediately before the first and second bolus administration and 1 h after each bolus was administered.  Serum samples were analyzed for total calcium.  Urinary pH was measured cow-side with a handheld meter (LAQUAtwin B-712, Horiba, Montpellier, FR).  Blood Beta-hydroxybutyrate (BHBA) concentrations were determined at 5, 8 and 11 d postpartum, using a handheld meter (Precision Xtra; Abbot, Alameda, CA).  Ketosis was defined as ≥ 1.4 mmol/L of BHBA in blood at least once during the sampling period.  Clinical endometritis was evaluated based on the observation of purulent or mucopurulent vaginal mucus retrieved with Metricheck (Simcro, NZ) from 28 to 40 d postpartum.  Treatment effects on serum calcium and urine pH were evaluated with linear mixed models with repeated measures using the MIXED procedure of SAS (Cary, NC).  The prevalence of ketosis and endometritis was evaluated with the chi-square option of the FREQ procedure (SAS).  Subclinical hypocalcemia (≤ 8.5 mg/dL) prior to treatment administration was 58% for control and treatment (P = 0.96).  One hour after bolus administration, serum calcium concentration was significantly greater in treated cows at first (8.65 vs. 8.01 mg/dL; P < 0.0001) and second (8.71 vs. 8.23 mg/dL; P < 0.001) bolus administration.  However, no significant differences were observed prior to second bolus administration (8.23 vs. 8.01 mg/dL; P = 0.12).  There was a treatment effect on urine pH (7.0 control vs. 6.1 treatment; P < 0.0001) and a significant treatment by time interaction (P = 0.02).  No treatment effects were observed on ketosis (26.7%; P = 0.97) or endometritis (47%; P = 0.93).  These results suggest that postpartum total serum calcium levels can be increased with oral bolus administration; however, serum calcium levels might not be maintained by the time the second bolus is administered.  

Keywords: Oral calcium supplementation, urine pH, serum calcium